[Marc, Michael, Yuhang]

First we realigned p-pol, BAB and green into OPO.

For BAB, we installed a power-meter before the homodyne.

We restarted the homodyne power supply (-19V, 0.06A) and confirmed the usual BAB transmission from OPO (~400 uW or ~200mV on homodyne sub DC).

We balance the homodyne using LO beam.

We realigned LO and BAB into AMC.

Then, we checked the OPO non-linear gain with MZ offset 4.2V.

We found T = 7.122 kOhm and p-pol freq = 180 MHz was maximizing amplification.

We measured with green (26mW) maximum of BAB of 1.04V while wihtout green it was 0.186V meaning a non-linear gain of about 5.4.

We lock CC1 and CC2 using the DDS3 config saved as '20230406_dds3'. Note that we found out that DAC1 and DAC3 cables of DDS3 are swapped. We should remember to modify accordingly the DDS3 config after reconnecting properly the cables.

Using the new SR785 we measure squeezing, anti-squeezing, shot-noise, homodyne noise and SR785 noise as attached in figure 1.

Note that the data are saved in .78D. To convert them into text file we have to save the data into the folder ./python/conversion and then use the command 'SRTRANS /Oasc /D SHOTN2.78D SHOTN2.txt' where SHOTN2 is the filename to convert.

Because we had to 'randomly' tune various gains to speed up debugging, we have some noise structure about 4 kHz. We will remeasure the OLTF to better tune their gains.

In any case, we measured about 5.9dB squeezing and 11.5 dB anti-squeezing !

This is compatible with our loss estimate in the wiki. We will measure squeezing again to see the EOM replacement effect on phase noise.